Pinto M E, Schrago C G, Miranda A B, Russo C A M
Departamento de Genética, Laboratório de Biodiversidade Molecular, Instituto de Biologia, UFRJ, Rio de Janeiro, RJ, Brasil.
Genet Mol Res. 2008 Oct 14;7(4):1031-44. doi: 10.4238/vol7-4gmr383.
In spite of the remarkable diversity of HIV-1 env genes, several amino acids are extremely conserved, probably due to functional constraints. One example is the proline found at the second position of the GPGR motif. Several viruses, however, bear substitutions at this site, for instance, GWGR subtype B variant. GWGR viruses are described in Brazil since the beginning of the epidemics, but the extent of their dispersion or the geographical origin of the variant remains unknown. In the present study, phylogenetic trees were constructed in order to study the origin and spread of this variant. All GWGR sequences as well as a subset of subtype B sequences available were included in the analyses. Analyses of differential selection were also performed on GWGR and non-GWGR sequences in order to unveil evolutionary novelties due to the action of positive selection. Although the GWGR variant was found at least in 23 countries, its expansion probably has a single origin, and Brazil is the epicenter.
尽管HIV-1 env基因具有显著的多样性，但由于功能限制，仍有几个氨基酸是高度保守的。一个例子是GPGR基序第二位的脯氨酸。然而，有几种病毒在该位点存在替代，例如GWGR B亚型变体。自疫情开始以来，巴西就有关于GWGR病毒的描述，但它们的传播范围或该变体的地理起源仍不清楚。在本研究中，构建了系统发育树以研究该变体的起源和传播。分析中纳入了所有GWGR序列以及可用的B亚型序列子集。还对GWGR和非GWGR序列进行了差异选择分析，以揭示正选择作用导致的进化新特征。尽管GWGR变体至少在23个国家被发现，但其扩张可能有单一起源，巴西是中心。
